The present invention relates to photographic apparatus which can be used to make exposures with artificial illumination of the subject. More specifically, the invention relates to improvements in photographic apparatus including a source of artificial light and any one of several types of cameras.
When an electronic flash unit is attached to a camera having an adjustable diaphragm, the latter is normally adjusted, either by hand or in automatic response to attachment of the flash unit, so as to define a lightadmitting aperture whose size is best suited for the making of exposures with artificial illumination of the subject. The f/stop which is selected for the making of exposures with flash depends primarily on the sensitivity of film in the camera body. The adjustability of diaphragm in the camera enables the user to make highly satisfactory exposures with flash because the user is in a position to select that f/stop which is best suited for the making of exposures with artificial illumination of the subject by taking into consideration the type of flash unit and/or other parameters, such as the aforementioned sensitivity of film in the camera body.
The just described flash unit cannot be used with or on a camera which does not have an adjustable diaphragm, i.e., wherein the single f/stop furnished by such nonadjustable diaphragm is not ideally suited (or is totally unsuited) for the making of exposures with flash. The same applies for cameras wherein the diaphragm is adjustable but can furnish only a limited number of f/stops not a single one of which is satisfactory for the making of acceptable exposures with flash.